what size dimmer switch to run 9 *12v 50w bulbs running off individual transformers?

Question

i would like them to run off just the one switch, so no need to alter wiring

Answer 1

A 450watt dimmer switch will do the job but you must check that the transformers are of the dim able type and also that if you have a living space on the floor above the fittings you should use fire hoods

Answer 2

If I understand your question correctly, you're saying you have nine 12VDC 50watt lamps each one on an individual transformer. Or possibly all nine lamps are running off one transformer, as in the Malibu landscape lighting sets? Regardless, be aware the standard dimmer will not work for this application as it is designed for dimming 120VAC incandescent bulb fixtures, whereas you have transformers in the circuit. You require a fluorescent light fixture dimmer, these are designed to handle transformer loads. A 1000 watt Lutron dimmer should work pretty well.

Answer 3

The dimmer switch will use more energy than the simple on/off switch and when the dimmer switch is set to dim it will use ( waste ) some of the energy that would have gone to the bulb , so you use the same amount of energy when the bulb is dimmed or when its on bright.

Answer 4

Need to calculate your minimum size:
9 ea x 50 W= 450 W

Apply 80% derating (oversize by 125%):
450W/.8 = 562.5 W (minimum dimmer size) or 5 Amps +/- @120 V.


If you are building this yourself, be sure to install fuses. Don't burn your house down over Christmas lights. Your are best off to buy purpose built U.L listed stuff. They test the dickens out of stuff so you don't burn your house down.

Answer 5

I would use a 3 gang dimmer..that is 3 dimmer buttons on one switch ,,so each switch supply 3 bulbs

Answer 6

A GOOD QUALITY one! (Lutron Rania Universal 450watt) no derating required. Or drop the lamps to 35 watt and use an MK 400va.

** the Wickes one suggested above will fry! it's only 250 watt rating.**

** Ignore Galileon, unless you're in the US, I wish that the US respondents would realise that we have different voltage and regulations, colour codes, and accessories in the UK. Do they really believe that the whole world uses the US electrical sytem??!!

Answer 7

You will need to use a low voltage dimmer switch, like this one available at Wickes for £6.89 or Screwfix Direct for £13.99:

click links to view:

http://www.wickes.co.uk/invt/710161

http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A331908&ts=56243&id=20886

Answer 8

if each bulb has its own transformer wouldnt you need 9 controls for them? or does ONE 110 volt line feed all 9 transformers? You werent clear on this... if one line feeds all 9..then indeed you are using 110 volts, however the transformers may not be dimable...